Following chief executive Ben Buckley's headline departure, Football Federation Australia has lost another key official - referees boss Mark Shield will leave at the end of the month after the governing body declined to turn his part-time job into a full-time position.

Shield, a two-time World Cup referee who also officiated the final of the 2006 Asian Champions League and during the 2007 FIFA Club World Cup, has only been employed at Whitlam Square for the past year, but was quick to impress many observers with the way he overhauled the referees structure.

Just last week, Shield unveiled a new selection process for referees in the A-League and W-League to widespread acclaim. It's believed Shield is leaving to take up a job outside football in central Queensland. "I have thoroughly enjoyed my time with FFA," he said. "The education and development of referees in Australia is something that I am very passionate about. This was a decision made for my family and my career."

However, Andy Harper, a Fox Sports pundit who is on the referees' technical advisory committee, believes the FFA have made a "big mistake" by not doing enough to keep Shield in the fold.>

"We should never have lost him. I don't understand for a second why the game allows itself to lose talent like this," Harper said. "Mark is a gun, he's been a godsend for the much-needed reform of the refereeing structure, and we're losing him. He was making terrific headway, he was exactly what we needed, and now he's going. He's going to be very hard to replace."

While new A-League boss Damien de Bohun admitted Shield would be a "loss", he remained confident a suitable replacement could be found: "We will work together over the coming weeks to ensure that the right candidate is selected to continue Mark's excellent work and ensure a smooth transition occurs."